Sony SPP-M920 Primary, Service Manual

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3.1.3 System Control Functions
1) Microcontroller. An 8-bit 80C32T2 microcontroller executes the program and controls the protocol logic and other hardware configura-
tion. It includes 16kbytes of mask-programmable ROM and 256bytes of RAM. It also includes an asynchronous serial port.
2) Synchronous Serial Port. The serial port provides a synchronous serial link to devices such as RF synthesizers, serial EEPROM's, etc.
3) Peripheral Ports. The peripheral ports are for general purpose I/O functions. One port is designed such that any change of state generates
an interrupt for the key scanning function.
4) Battery Level Detector. The battery level detector reports the low battery condition to prevent misoperation when batteries are low. It also
emits a dead battery control signal which can be used to hold the device in a disabled, low power state and high level detection for battery
charging control.
5) Watchdog Timer. The watchdog timer protects the system from errant software by periodically issuing a reset unless serviced by software.
6) Wakeup Timer. The wakeup timer is a multivibrator controlled by external passive components to effect a low power periodic wakeup for
call detection.
7) Interrupt Controller. The interrupt controller structures the various interrupts for manageable service by the microcontroller.
8) Clock Generator. The clock generator creates required internal timing signals from the crystal operating at 18.25MHz. It also generates a
PLL reference at the crystal frequency.
9) Address decoder. The address decoder generates strobes accessing selected address spaces in the device.
Figure 5. AMD ASIC-Internal Structure Diagram
TXBB
FRAME
FORMATTER
PARALLEL
PORTS
WAKEUP
TIMER
PROTOCOL FUNCTIONS
AUDIO FUNCTIONS
ADPCM
CODEC
and
DTMF
GENERATOR
INTERRUPT
CONTROLLER
AUDIO
FRONT
END
DIGITAL
RINGER
RXBB
BATMON
TST0
AIN
AOP
SDIN
SDOUT
MODE0
MODE1
SCLK
AON
RING
ALE
/PSEN
P0 [7 : 0]
/INT0
/INT1
BIASING
SYNCHRONOUS
SERIAL PORT
MODE
SELECT
80C32T2
Microcontroller
ROM : 16 kbytes
RAM : 256 bytes
IREF
CFILT
TST1
MON [3 : 0]
P4 [4 : 0]
P5 [4 : 0]
P6 [5 : 0]
WAKEUP
WATCHDOG
TIMER
/RESET
PLLREF
XTAL1
XTAL2
BATTERY
DETECT
CLOCK
GENERATOR
RAM
INTERNAL 256bytes
BAT
DEAD
P1 [7 : 0]
P2 [6 : 0]
P3 [1 : 0]
P3 [7 : 6]
SYSTEM CONTROL FUNCTIONS